Actuator having an internal conductive path

ABSTRACT

An actuator includes a piston and a housing. The piston includes a piston shaft that is configured to reciprocate within the housing. The actuator also includes a conductor coupled to the piston within the housing and configured to electrically couple the piston to the housing as the piston reciprocates within the housing.

FIELD OF THE DISCLOSURE

The present disclosure relates to an actuator having an internalconductive path.

BACKGROUND

Use of composite materials to form components of vehicles has increasedas new composite material and manufacturing processes have becomeavailable. At the same time, many modern vehicles rely heavily onelectronic systems. Composite materials tend not to be very conductive,so grounding of components can be a challenge. For example, when anactuator is coupled to a conductive frame, such as a metal, theconductive frame may provide a conductive path between a piston of theactuator and a cylinder of the actuator. When composite materials areused for the frame, there may be no conductive path between the pistonof the actuator and the cylinder of the actuator through the frame.Without a conductive path, an electric potential of the piston and ofthe cylinder can become unequal.

SUMMARY

In a first aspect of the disclosure, an actuator includes an actuatorhousing and a piston having a piston shaft. The piston is configured toreciprocate within the housing. The actuator also includes a conductorcoupled to the piston within the housing. The conductor is configured toelectrically couple the piston to the housing as the piston reciprocateswithin the housing.

In a second aspect of the disclosure, a structure (such as a vehicle orbuilding) includes an actuator. The actuator includes a housing and apiston having a piston shaft. The piston is configured to reciprocatewithin the housing. The actuator also includes a conductor coupled tothe piston within the housing. The conductor is configured toelectrically couple the piston to the housing as the piston reciprocateswithin the housing.

In a third aspect of the disclosure, a method includes coupling aconductor to a piston such that the conductor is in electrical contactwith the piston. The method also includes inserting the conductor and atleast a portion of the piston into an actuator housing. Further, themethod includes coupling the piston to the actuator housing using aretainer assembly such that the conductor maintains electrical contactwith the piston and with the actuator housing during reciprocation ofthe piston within the housing.

One advantage of the actuator of the present disclosure is that theactuator includes a conductor that provides an electrically conductivecontact area to provide a current path between a piston shaft and anactuator housing. The conductor is disposed within the actuator housingand maintains the current path throughout a range of motion of theactuator. Additionally, the features, functions, and advantages thathave been described can be achieved independently in various embodimentsor may be combined in yet other embodiments, further details of whichare disclosed with reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of an example of an actuator withinternal features that provide a conductive path;

FIG. 2 illustrates internal features of the actuator of FIG. 1;

FIG. 3 illustrates an example of a split ring conductor;

FIG. 4 illustrates an example of a split ring finger conductor

FIG. 5 is a cross-sectional view of another example of an actuator withinternal features that provide a conductive path;

FIG. 6A is a cross-sectional view of another example of an actuator withinternal features that provide a conductive path;

FIG. 6B is a cross-sectional view of another example of an actuator withinternal features that provide a conductive path;

FIG. 7A is a cross-sectional view of another example of an actuator withinternal features that provide a conductive path;

FIG. 7B is a cross-sectional view of another example of an actuator withinternal features that provide a conductive path;

FIG. 8 is a flow chart of an illustrative example of a method ofassembling an actuator; and

FIG. 9 is a block diagram of an illustrative embodiment of an aircraftthat includes an actuator with a flight management system.

Each figure shown in this disclosure shows a variation of an aspect ofthe embodiments presented, and only differences will be discussed indetail.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure are described belowwith reference to the drawings. In the description, common features aredesignated by common reference numbers throughout the drawings.

The figures and the following description illustrate specific exemplaryembodiments. It will be appreciated that those skilled in the art willbe able to devise various arrangements that, although not explicitlydescribed or shown herein, embody the principles described herein andare included within the scope of the claims that follow thisdescription. Furthermore, any examples described herein are intended toaid in understanding the principles of the disclosure and are to beconstrued as being without limitation. As a result, this disclosure isnot limited to the specific embodiments or examples described below, butby the claims and their equivalents.

The present disclosure relates to actuators that include internalfeatures that provide a conductive path between an actuator housing anda piston. For example, the actuator may include a conductor coupled tothe piston within the actuator housing. The conductor is configured toelectrically couple the piston to the actuator housing as the pistonreciprocates within the actuator housing. In some examples, the actuatormay include one or more additional components, such as a gland, a guide,a spring element, and a retainer, that are configured to maintainelectrical contact between the conductor, the piston shaft, and theactuator housing.

FIG. 1 is a cross-sectional view of an example of an actuator 100 withmultiple internal features that provide a conductive path (e.g., a pathto ground 190). In use, the actuator 100 may be coupled to a vehicle(not shown). For example, when the vehicle is an aircraft, the aircraftmay include one or more wings and a fuselage, which may include acomposite structural member, a metallic structural member, or acombination thereof, coupled to the actuator housing. In other examples,the vehicle may include or correspond to a motorcycle, an automobile, arailed vehicle (e.g., a train or tram), a watercraft, another type ofaircraft; a spacecraft; or a combination thereof, as illustrative,non-limiting examples. In other examples, the actuator 100 may becoupled to a fixed platform, such as a door, a lifting mechanism, etc.

The actuator 100 includes an actuator housing 102 and a piston 120. Theactuator housing 102 defines a cylinder 104 (e.g., a cavity within theactuator housing 102). The actuator housing 102 may include or may beformed of a conductive material. In some uses, the actuator housing 102may be grounded as indicated in FIG. 1 by a ground symbol 180.

The piston 120 includes a piston shaft 122 and a piston head 124. Thepiston 120 is configured to reciprocate within the actuator housing 102as the piston head 124 moves in a direction of travel 126 within thecylinder 104. For example, the piston head 124 may move in the directionof travel 126 due to a pressure of a working fluid of a pneumatic orhydraulic system applied to either side of the piston head 124.

The actuator housing 102 is configured to receive one or morecomponents, such as a gland 114, a conductor 106, a guide 108, a springelement 112, and a retainer 110 in FIG. 1. Each of the components may becoupled to the actuator housing 102 and may surround (e.g., encircle)the piston shaft 122. For example, each of the components may include acentral opening (not shown) having an internal diameter that may begreater than or equal to a diameter of the piston shaft 122. Theinternal diameter of each of the components enables the one or morecomponents to encircle the diameter of the piston shaft 122.

The gland 114 may be coupled to the actuator housing 102 and maysurround the piston shaft 122. To illustrate, the piston shaft 122 mayextend through a central opening of the gland 114 into the cylinder 104,as explained above. The gland 114 may be electrically coupled to theactuator housing 102. For example, the gland 114 may be in directphysical contact with the actuator housing 102 to provide the conductivepath between the gland 114 and the actuator housing 102. The gland 114may include or be formed of a high wear resistance material, such asaluminum, nickel, bronze, or a combination thereof, as illustrative,non-limiting examples. The gland 114 may include a recess (shown in FIG.2) configured to receive at least a portion of the conductor 106. Thegland 114 may be configured to seal the cylinder 104 to inhibit movementof a pressurized working fluid (e.g., hydraulic fluid) out of thecylinder 104. The gland 114 may include a primary seal, a secondaryseal, a buffer seal, bearing elements, wiper/scraper and a static seal,or a combination thereof, as illustrative, non-limiting examples.

The conductor 106 may be coupled to the piston shaft 122 within theactuator housing 102. To illustrate, the piston shaft 122 may extendthrough a central opening of the conductor 106, as explained above. Theconductor 106 may be configured to electrically couple the piston 120 tothe actuator housing 102 throughout a range of motion of the piston 120,e.g., as the piston shaft 122 reciprocates within the actuator housing102. Thus, the conductor 106 may provide a current path between thepiston 120 and the actuator housing 102, such as the path to ground 190from the piston shaft 122 to the actuator housing 102. The conductor 106may have elastic characteristics such that at least a portion of theconductor 106 (e.g., a contact area) maintains contact with the piston120 while the piston 120 slides relative to the conductor 106 duringreciprocation of the piston 120 within the actuator housing 102. Thus,while the piston shaft 122 moves relative to the actuator housing 102,the conductor 106 maintains contact with both the piston shaft 122 andthe actuator housing 102 (e.g., fixed contact with the actuator housing102 via the gland 114 and sliding contact with the piston shaft 122) toprovide the conduction path. In some implementations, the conductor 106may include a split ring conductor 300 as described within reference toFIG. 3 or a split ring finger conductor 400 as described with referenceto FIG. 4.

The guide 108 may be coupled to the piston shaft 122 within the actuatorhousing 102. To illustrate, the piston shaft 122 may extend through anopening of the guide 108, as explained above. In a particularimplementation, the guide 108 includes a first face and a second face.The first face, the second face, or both, may include a recessed area.For example, the recessed area of the first face may be placed incontact with the conductor 106, and the recessed area of the second facemay be placed in contact with the spring element 112. The guide 108 maybe configured to enable the spring element 112 to distribute an axialforce applied by the spring element 112 to the conductor 106. The axialforce applied to the conductor 106 may facilitate maintaining contactbetween the conductor 106 and the gland 114. For example, the axialforce may keep at least a portion of the conductor 106 in contact withthe gland 114 as the piston shaft 122 reciprocates along the directionof travel 126 within the actuator housing 102. The spring element 112may be coupled to the piston shaft 122. The piston shaft 122 may extendthrough an opening of the spring element 112, as explained above. Thespring element 112 may include or be formed of an elastomer material,such as silicon, as illustrative, non-limiting example.

The retainer 110 may be coupled to the gland 114 and may surround thepiston shaft 122. To illustrate, the piston shaft 122 may extend throughan opening of the retainer 110, as explained above. The retainer 110 maybe threaded to receive a retainer assembly including the spring element112, the guide 108, the conductor 106, at least a portion of the gland114, or a combination thereof. The retainer assembly may be configuredto retain the conductor 106 in electrical contact with the gland 114. Ina particular implementation, the retainer 110 may have a recessconfigured to receive the spring element 112, the guide 108, theconductor 106, at least a portion of the gland 114, or a combinationthereof. The threaded portion may be configured to retain the conductor106 in electrical contact with the gland 114. For example, a portion ofthe gland 114 may be threaded to receive the retainer 110, the springelement 112, the guide 108 and the conductor 106, as shown in FIG. 1. Inthis example, the threads of the retainer 110 may be coupled to thethreads of the gland 114 to retain the conductor 106, the guide 108 andthe spring element 112 within an opening in the gland 114.

During operation, the piston 120 may reciprocate within the actuatorhousing 102 as the piston head 124 moves in the direction of travel 126within the cylinder 104. The conductor 106 may be retained in electricalcontact with the actuator housing 102 by the elastic characteristics ofthe conductor 106, the spring element 112, the guide 108, or acombination thereof. Additionally, the conductor 106 slides along thepiston shaft 122 as the piston 120 reciprocates. The electrical contactis maintained throughout a full range of motion of the piston 120. Thus,the conductor 106 provides a conductive path (such as the path to ground190) between the piston 120 and the actuator housing 102. The conductivepath may prevent uneven buildup of charge between the piston 120 and theactuator housing 102. Additionally the path to ground 190 may enabledissipation of current due to events, such as a lightning strike.

FIG. 2 illustrates internal features of the actuator 100 of FIG. 1. Theinternal features illustrated in FIG. 2 include a gland 214, a conductor206, a guide 208, a spring element 212, and a retainer 210.

The gland 214 may correspond to the gland 114 of FIG. 1. The gland 214,as described with reference to FIG. 1, may be coupled to the actuatorhousing 102 and may surround the piston shaft 122. The gland 214 mayinclude an inner portion 256 that includes threading. The threading ofthe inner portion 256 may be configured to receive at least a portion ofthe retainer 210. The gland 214 may also include an outer portion 252that includes threading. The threading of the outer portion 252 may beconfigured to couple the gland 214 to an actuator housing. The gland 214may include a recess. The recess, as illustrated by section 220, may beconfigured to receive at least a portion of the conductor 206, the guide208, the spring element 212, the retainer 210, or a combination thereof.The gland 214 may include a bottom portion 254 that is retained indirect physical contact with the actuator housing 102. The bottomportion, the outer portion 252, or both may provide a conductive pathbetween the gland 214 and the actuator housing 102. In someimplementations, the bottom portion 254 may be configured to seal thecylinder 104 to inhibit movement of a pressurized working fluid (e.g.,hydraulic fluid) past an interface between the actuator housing 102 andthe cylinder 104. The bottom portion 254 may include a primary seal, asecondary seal, a buffer seal, bearing elements, wiper/scraper and astatic seal, or a combination thereof, as illustrative, non-limitingexamples.

The conductor 206 may correspond to the conductor 106 of FIG. 1. Theconductor 206, as described with reference to FIG. 1, may be coupled tothe piston shaft 122 within the actuator housing 102, as explainedabove. The conductor 206 may be configured to electrically couple thepiston 120 to the actuator housing 102 (via a first contact area 260 anda second contact area 262) throughout a range of motion of the piston120, e.g., as the piston shaft 122 reciprocates within the actuatorhousing 102. Thus, the conductor 206 may provide a current path betweenthe piston 120 and the actuator housing 102. The conductor 206 may haveelastic characteristics, such that at least a portion of the secondcontact area 262 maintains contact with the piston 120 and at least aportion of first contact area 260 maintains contact with the gland 214,while the piston 120 slides relative to the conductor 206 duringreciprocation of the piston 120 within the actuator housing 102. Whilethe piston shaft 122 moves relative to the actuator housing 102, thefirst contact area 260 slides along the piston shaft 122 and maintainselectrical contact with the piston shaft 122. Additionally, the secondcontact area 262 remains in relatively static contact with the gland214. In some implementations, the conductor 206 may include a split ringas described within reference to FIG. 3.

The guide 208 may correspond to the guide 108 of FIG. 1. The guide 208,as described with reference to FIG. 1, may be coupled to the pistonshaft 122 within the actuator housing 102. In a particularimplementation, the guide 208 includes a first face 230 and a secondface 232. The first face 230, the second face 232, or both, may includea recessed area 234, 236. For example, the recessed area 234 of thefirst face 230 may be placed in contact with the conductor 206, and therecessed area 236 of the second face 232 may be placed in contact withthe spring element 212. The guide 208 may be configured to enable thespring element 212 to apply a substantially uniform force to theconductor 206. The substantially uniform force applied to the conductor206 may facilitate maintaining contact between the conductor 206 and thegland 214. For example, the substantially uniform force may keep atleast a portion of the first contact area 260 of the conductor 206 incontact with the gland 214, as the piston shaft 122 reciprocates alongthe direction of travel 126 within the actuator housing 102. The springelement 212 may correspond to the spring element 112. The spring element212 may be coupled to the piston shaft 122, as explained above. Thespring element 212 may include a first face 270. The first face 270 ofthe spring element 212 may be configured to apply a force to therecessed area 236 of the second face 232 of the guide 208 to facilitatemaintaining contact between the conductor 206 and the gland 214.

The retainer 210 may correspond to the retainer 110 of FIG. 1. Theretainer 210, as described with reference to FIG. 1, may be coupled tothe gland 214 and may surround the piston shaft 122. The retainer 210may include an inner portion 280 configured to receive a retainerassembly, including the spring element 212, the guide 208, the conductor206, or a combination thereof. The retainer assembly may be configuredto retain the conductor 206 in electrical contact with the gland 214.The retainer 210 may include an outer portion 282 that includesthreading. The threaded outer portion 282 may be configured to receiveand couple to the threading of the inner portion 256 of the gland 214.In operation, the threaded outer portion 282 may be configured to retainthe conductor 206 in electrical contact with the gland 214.

Although FIGS. 1 and 2 illustrate the retainer 210 and the gland 214configured such that the retainer 210 is retained within an opening ofthe gland 214, in other examples, a portion of the gland 214 may bereceived within an opening of the retainer 210. For example, the innerportion 280 of the retainer 210 may include threading. In this example,at least a portion of the outer portion 252 of the gland 214 may includethreading configured to couple to the threading of the inner portion280. In yet another example, the actuator housing may be configured toreceive the gland 214 and the retainer 210 and another mechanism may beused to both retain the gland 214 in contact with the actuator housingand to retain the retainer 210 in contact with the gland 214 or theactuator housing.

FIG. 3 illustrates an example of a split ring conductor 300. The splitring conductor 300 may correspond to the conductor 106 of FIG. 1 or theconductor 206 of FIG. 2. The split ring conductor 300 includes a curvedbody 312 having a first end 302 and a second end 304.

The curved body 312 may be formed of or include a conductive material.For example, the curved body 312 may be formed or include of aconductive metal. Additionally, the conductive material may be flexibleto enable the curved body 312 to elastically deform, e.g., to fittightly around the piston shaft. To illustrate, the curved body 312defines a central opening 308 configured to receive the piston shaft.The central opening 308 may have a diameter that is less than a diameterof the piston shaft. The first end 302 and the second end 304 areseparated by a gap 310. The gap 310 has a first dimension (e.g.,distance between the first end 302 and the second end 304) when thecurved body 312 is in a neutral or un-flexed position. When the curvedbody 312 is placed around the piston shaft, since the diameter of thecentral opening 308 is less than the diameter of the piston shaft, thegap 310 may increase due to flexing of the curved body 312.

Further, the curved body 312 is shaped such that a thickness 306 of thecurved body 312 is greater (e.g., thicker) in a region between the firstend 302 and the second end 304 than a thickness at the first end 302 andthe second end 304. Stated another way, the curved body 312 taperstoward each end 302, 304. The tapering thickness enables the curved body312 to apply relatively even pressure around a circumference of thepiston shaft. In another example, the thickness of the curved body 312is uniform between the first end 302 and the second end 304.

The split ring conductor 300 includes a first elongated member 320coupled to the first end 302 and extending radially from the curved body312. The split ring conductor 300 also includes a second elongatedmember 322 coupled to the second end 304 and extending radially from thecurved body 312. In some implementations, the first end 302, the secondend 304, or both, may enable application of a relatively uniform axialforce (e.g., a force in a direction corresponding to an axis of thepiston shaft) to the split ring conductor 300. For example, as describedwith reference to FIG. 1, the split ring conductor 300 may be coupled tothe gland by a retainer assembly that includes a retainer, a springelement, and a guide. In this example, a front face 314 of the curvedbody 312 may contact the gland (e.g., the gland 114 of FIG. 1), and aback face (not shown in the perspective illustrated in FIG. 3) of thesplit ring conductor 300 may contact the guide. In this example, thespring element is configured to press against (e.g., apply a force inthe axial direction to) the retainer and to press against (e.g., apply aforce in the axial direction to) the guide. Further, in this example,the guide is configured to press against (e.g., apply a force in theaxial direction to) the split ring conductor 300. The first elongatedmember 320 and the second elongated member 322 provide surfaces near thefirst and second ends 302, 304, respectively, to receive the forceapplied by the guide. Thus, rather than the guide pressing unevenly onthe split ring conductor 300 (due to the much greater surface area ofthe thicker region of the curved body relative to the ends 302, 304),the elongated members 320, 322 enable the guide to apply a relativelyuniform axial force to the split ring conductor 300.

FIG. 4 illustrates an example of a split ring finger conductor 400. Thesplit ring finger conductor 400 may correspond to the conductor 106 ofFIG. 1 or the conductor 206 of FIG. 2.

The split ring finger conductor 400 includes a curved body 440 having afirst end and a second end separated by a gap 408. The curved body 440may be formed of or include a conductive material. For example, thecurved body 440 may be formed or include of a conductive metal.Additionally, the conductive material may be flexible to enable thecurved body 440 to elastically deform, e.g., to fit tightly around thepiston shaft.

To illustrate, in FIG. 4, the curved body 440 defines a central opening410 configured to receive the piston shaft. The central opening 410 mayhave a diameter that is less than a diameter of the piston shaft. Thegap 408 has a first dimension (e.g., a distance between the first endand the second end) when the curved body 440 is in a neutral orun-flexed position. When the curved body 440 is placed around the pistonshaft, since the diameter of the central opening 410 is less than thediameter of the piston shaft, the gap 408 may increase due to flexing ofthe curved body 440.

The curved body 440 also includes a plurality of spring fingers, such asa first spring finger 402 and a second spring finger 404. A recess ornotch separates each pair of adjacent spring fingers. For example, arecess 406 is between the first spring finger 402 and the second springfinger 404. The fingers are coupled to a non-finger portion 412 of thecurved body 440 (e.g., a ring of material below the fingers in the viewillustrated in FIG. 4). In a particular embodiment, the spring fingersand the curved body 440 are formed as a single piece. For example, ametal sheet may be cut to a length corresponding to a circumference ofthe curved body 440. Recesses may be cut, stamped, or otherwise formedin the sheet to define finger regions and the non-fingered portion. Thefinger regions may be bent, as illustrated in callout 430 of FIG. 4, toform the spring fingers. Subsequently, the sheet, including the springfingers, may be bent to form the curved body 440.

In FIG. 4, each spring finger includes a primary spring portion 414, acontact portion 416 and a backing spring portion 418 coupled to thenon-fingered portion 412 of the curved body 440. The primary springportion 414 and the backing spring portion 418 may flex to enable thecontact portion 416 to remain in contact with and apply a pressureagainst the piston shaft. The primary spring portion 414 and the backingspring portion 418 provide conductive paths between the contact portion416 and the non-fingered portion 412. The non-fingered portion 412, andpotentially backs of one or more of the fingers, may contact the glandor portions of a retaining assembly to provide a conductive path betweenthe piston shaft and the gland. The contact portions 416 slide along thepiston shaft as the piston reciprocates within the actuator housing.

FIG. 5 is a cross-sectional view of another example of an actuator 500with multiple internal features that provide a conductive path (e.g., apath to ground 190). In some implementations, the actuator 500 of FIG. 5includes the actuator housing 102, the cylinder 104, the piston 120, thepiston shaft 122, the piston head 124, the gland 114, the conductor 106,the guide 108, the spring element 112, and the path to ground 190 ofFIG. 1. The actuator 500 further includes the retainer 510.

The retainer 510 may correspond to the retainer 110 of FIG. 1. Theretainer 510 may be coupled to the gland 114 and may surround the pistonshaft 122. To illustrate, the piston shaft 122 may extend through anopening of the retainer 510, as explained above. The retainer 510 may beconfigured to receive a retainer assembly including the spring element112, the guide 108, the conductor 106, at least a portion of the gland114, or a combination thereof. The retainer assembly may be configuredto retain the conductor 106 in electrical contact with the gland 114.The retainer 510 may include a threaded portion adjacent to the recess.The threaded portion may be configured to couple the retainer 510 to atleast a portion of the gland 114 to retain the conductor 106 inelectrical contact with the gland 114.

FIG. 6A is a cross-sectional view of another example of the actuator 600with multiple internal features that provide a conductive path (e.g., apath to ground 190). In some implementations, the actuator 600 of FIG. 6includes the actuator housing 102, the cylinder 104, the piston 120, thepiston shaft 122, the piston head 124, the gland 114, the retainer 110,and the path to ground 190 of FIG. 1. The actuator 600 further includesthe conductor 606.

The conductor 606 may correspond to the conductor 106 of FIG. 1. In FIG.6, the conductor 606 includes a split ring finger conductor, such as thesplit ring finger conductor 400 of FIG. 4. The conductor 606 includes aplurality of fingers that are disposed circumferentially around theconductor 606. The spring portion may be configured to enable thecontact portion to remain in contact with the piston shaft 122 and toapply a pressure against the piston shaft 122, while the piston shaft122 reciprocates within the actuator housing 102. The contact of thecontact portion to the piston shaft 122 provides an electricallyconductive path (e.g., the path to ground 190) between the piston shaft122 and the actuator housing 102 to safely pass a current from thepiston shaft 122 to the actuator housing 102.

FIG. 6B is a cross-sectional view of another example of the actuator 600with multiple internal features that provide a conductive path (e.g., apath to ground 190). In some implementations, the actuator 600 of FIG. 6includes a housing 650, a piston 652, a ball nut 672, a ballscrew 654,an integral brake assembly 656, a slip clutch 658, an output gear 660, apinion gear 662, a spur gearing 664, a motor 670, and the conductor 606.

In the implementation illustrated in FIG. 6B, the motor 670 may beconfigured to control operations (e.g., movement) of the actuator 600.The motor 670 is coupled to the spur gearing 664. The spur gearing 664is coupled to the pinion gear 662. For example, the spur gearing 664 mayinclude a first structure and the pinion gear 662 may include a secondstructure. The first structure and the second structure may includeteeth configured to interlock the spur gearing 664 and the pinion gear662 and transmit rotational motion (e.g., torque).

The pinion gear 662 is coupled to the output gear 660. For example, thepinion gear 662 may be known as an “input gear” or drive gear thatprovides rotational motion to the output gear 660 (e.g., the gear thatis being turned). The output gear 660 is coupled to the slip clutch 658.The slip clutch 658 is configured to limit torque by slipping. The slipclutch 658 may be coupled to a drive shaft (not shown) and the driveshaft may be coupled to the integral brake assembly 656 and to theballscrew 654. The ballscrew 654 may be positioned within a cavity 668defined by the housing 650. The ballscrew 654 is coupled to the ball nut672. Rotation of the ballscrew 654 provides translational motion of theball nut 672. The ball nut 672 is coupled to the piston 652. The housing650 may correspond to the actuator housing 102 of FIG. 1.

The housing 650 may include the piston 652 and the conductor 606. Theconductor 606 may correspond to the conductor 106 of FIG. 1. In FIG. 6,the conductor 606 may include a split ring conductor, such as the splitring conductor 300 of FIG. 3. In another example the conductor 606 mayinclude a split ring finger conductor, such as the split ring fingerconductor 400 of FIG. 4. The conductor 606 is configured to slide alongthe piston 652 as the piston 652 moves within a cavity 668. Electricalcontact is maintained throughout a full range of motion of the piston652. Thus, the conductor 606 provides a conductive path (such as thepath to ground 190) between piston 652 and the housing 650. Theconductive path may prevent uneven buildup of charge between piston 652and the housing 650. Additionally the path to ground 190 may enabledissipation of current due to events, such as a lightning strike.

FIGS. 7A and 7B are cross-sectional views of additional examples of anactuator 700 and 750 with multiple internal features that provide aconductive path (e.g., a path to ground 190). In some implementations,the actuator 700 and 750 of FIGS. 7A and 7B includes the actuatorhousing 102, the cylinder 104, the piston 120, the piston shaft 122, thepiston head 124, and the path to ground 190 of FIG. 1. The actuator 700and 750 further includes a gland 714 and a conductor 706.

The gland 714 may correspond to the gland 114 of FIG. 1. The gland 714may be electrically coupled to the actuator housing 102. For example,the gland 714 may be in direct physical contact with the actuatorhousing 102 to provide the conductive path between the gland 714 and theactuator housing 102. The gland 714 may be configured to seal thecylinder 104 to inhibit movement of a pressurized working fluid (e.g.,hydraulic fluid) past an interface between the actuator housing 102 andthe cylinder 104. The gland 714 may include a primary seal, a secondaryseal, a buffer seal, bearing elements, wiper/scraper and a static seal,or a combination thereof, as illustrative, non-limiting examples.

In the implementation illustrated in FIGS. 7A and 7B, the conductor 706is positioned with the cylinder 104, rather than within the housing andexternal to the cylinder 104 as in FIGS. 1, 5 and 6. Additionally,whereas the conductors 106 and 606 of FIGS. 1, 5, and 6, respectively,maintain relatively stationary contact with the gland and slidingcontact with the piston shaft, in FIGS. 7A and 7B, the conductor 706 hasa first end 703 coupled to or in contact with the gland 714 and a secondend 725 coupled to or in contact with the piston shaft 122 or a firstside of the piston head 124. For example, the first end 703 of theconductor 706 may be connected to the gland 714 using a fastener orusing a metal joining technique (such as welding, soldering or brazing).Likewise, the second end 725 of the conductor 706 may be connected tothe piston head 124 using a fastener or using a metal joining technique(such as welding, soldering or brazing). In the example illustrated inFIG. 7A, the conductor 706 may be a conductive bellow In this example,tension of the conductor 706 may maintain the conductor 706 in contactwith one or both of the gland 714 and the piston head 124 throughout arange of motion of the piston head 124. In the example illustrated inFIG. 7B, the conductor 706 is coiled to form a spring. In this example,spring tension of the conductor 706 may maintain the conductor 706 incontact with one or both of the gland 714 and the piston head 124throughout a range of motion of the piston head 124.

In the implementation illustrated in FIG. 7B, a second conductor 707 isalso positioned with the cylinder 104. For example, the piston head 124may include an O-ring 728 that fauns a seal with the wall of thecylinder 104 to divide the cylinder 104 into two chambers. In thisexample, the conductor 706 may positioned within a first chamber and thesecond conductor 707 may be positioned with a second chamber. The secondconductor 707 has a first end 705 coupled to or in contact with aninterior wall of the cylinder 104 (e.g., a portion of the actuatorhousing 102) and a second end 727 coupled to or in contact with a secondside of the piston head 124. For example, the first end 705 of thesecond conductor 707 may be connected to the interior wall of thecylinder 104 using a fastener or using a metal joining technique (suchas welding, soldering or brazing). Likewise, the second end 727 of thesecond conductor 707 may be connected to the piston head 124 using afastener or using a metal joining technique (such as welding, solderingor brazing). As another example, the second conductor 707 may be coiledto form a spring, as illustrated in FIG. 7B. In this example, springtension of the second conductor 707 may maintain the second conductor707 in contact with one or both of the interior wall of the cylinder 104and the piston head 124 throughout a range of motion of the piston head124.

Since the conductor 706 may coil around the piston shaft 122, the pistonshaft 122 acts as a retaining assembly to keep the conductor 706 in adesired orientation. However, since no shaft is present on the side ofthe cylinder 104 that includes the second conductor 707, the secondconductor 707 may be retained in a desired orientation by fixing bothends 705, 727 or by sizing coils of the second conductor 707 to just fitwithin the cylinder 104 (e.g. to contact or nearly contact the walls ofthe cylinder 104).

Although FIG. 7B illustrates an implementation that includes twoconductors 706, 707, in other implementations, only one of theconductors 706, 707 may be present. For example, the actuator 700 mayinclude the conductor 706 without the second conductor 707.Alternatively, the actuator 700 may include the second conductor 707without the conductor 706.

Thus, the conductor 706, the second conductor 707, or both, may providea current path between the piston 120 and the actuator housing 102, suchas the path to ground 190 from the piston shaft 122 to the actuatorhousing 102. The conductor 706, the second conductor 707, or both, mayexpand and contract as the piston shaft 122 reciprocates within theactuator housing 102. For example, in an implementation that includesthe conductor 706, at least a portion of the conductor 706 remains inelectrical contact with the piston 120 (e.g., the second end 725 of theconductor 706 remains in contact with the first side of the piston head124) and at least a portion of the conductor 706 remains in electricalcontact with the actuator housing 102 (e.g., the first end 703 of theconductor 706 remains in contact with the gland 714 which is in contactwith actuator housing 102) while the piston 120 reciprocates within theactuator housing 102. As another example, in an implementation thatincludes the second conductor 707, at least a portion of the secondconductor 707 remains in electrical contact with the piston 120 (e.g.,the second end 727 of the second conductor 707 remains in contact withthe second side of the piston head 124) and at least a portion of thesecond conductor 707 remains in electrical contact with the actuatorhousing 102 (e.g., the first end 705 of the second conductor 707 remainsin contact with the interior wall of the cylinder) while the piston 120reciprocates within the actuator housing 102. Thus, while the pistonshaft 122 moves relative to the actuator housing 102, the conductor 706maintains contact with both the piston shaft 122 and the actuatorhousing 102 to provide the electric conduction path.

FIG. 8 is a flow chart of an illustrative example of a method 800 ofassembling an actuator. The method 800 enables assembly of an actuatorthat includes internal features that provide a conductive path between apiston shaft of the actuator and an actuator housing of the actuator.For example, the actuator assembled using the method 800 may correspondto the actuator 100 of FIG. 1, the actuator 500 of FIG. 5, the actuator600 of FIGS. 6A and 6B, the actuator 700 of FIG. 7A, or the actuator 750of FIG. 7B.

The method 800 includes, at 802, coupling a conductor to a piston suchthat the conductor is in electrical contact with the piston. Forexample, the conductor 106 of FIGS. 1 and 5 or the conductor 606 of FIG.6 may be coupled to the piston shaft 122 by extending the piston shaft122 through an opening of the conductor. The conductor may have a splitring configuration, such as the split ring conductor 300 of FIG. 3 orthe split ring finger conductor 400 of FIG. 4. The split ring may definean opening that has a diameter that is less than a diameter of thepiston shaft. Accordingly, when the conductor is coupled to the pistonshaft, the conductor may remain in contact with the piston shaft whilesliding along the piston shaft as the piston reciprocates within theactuator housing.

In another example, the conductor may include the conductor 706 or thesecond conductor 707 of FIG. 7B. In this example, the conductor may becoupled to a piston head of the piston. To illustrate, the second end725 of the conductor 706 may be coupled to the first side of the pistonhead 124 (e.g., using a fastener, a metal joining process, spring force,or another coupling process). As another illustration, the second end727 of the second conductor 707 may be coupled to the second side of thepiston head 124 (e.g., using a fastener, a metal joining process, springforce, or another coupling process).

In addition to the conductor, the method 800 may include coupling othercomponents to the piston shaft. For example, during assembly of theactuator 100 of FIG. 1, the gland 114, the guide 108, the spring element112, and the retainer 110 may also be coupled to the piston 120. Toillustrate, each of the retainer 110, the spring element 112, the guide108, the conductor 106, and the gland 114 may be coupled to the pistonshaft 122, and subsequently, the piston head 124 may be coupled to thepiston shaft (e.g., using threading of the piston shaft 122 and thepiston head, using a metal joining technique, or using a fastener). Asanother example, during assembly of the actuator 500 of FIG. 5, theretainer 510, the spring element 112, the guide 108, the conductor 106,and the gland 114 may be coupled to the piston shaft 122, andsubsequently, the piston head 124 may be coupled to the piston shaft 122(e.g., using threading of the piston shaft 122 and the piston head,using a metal joining technique, or using a fastener). As yet anotherexample, during assembly of the actuator 600 of FIG. 6A, the retainer110, the conductor 606 and the gland 114 may be coupled to the pistonshaft 122, and subsequently, the piston head 124 may be coupled to thepiston shaft 122 (e.g., using threading of the piston shaft 122 and thepiston head, using a metal joining technique, or using a fastener). Asstill another example, during assembly of the actuator 700 or actuator750 of FIGS. 7A and 7B, the gland 714 and the conductor 706 may becoupled to the piston shaft 122, and subsequently, the piston head 124may be coupled to the piston shaft 122 (e.g., using threading of thepiston shaft 122 and the piston head, using a metal joining technique,or using a fastener). Additionally, or in the alternative, duringassembly of the actuator 700 or the actuator 750 of FIGS. 7A and 7B, thegland 714 may be coupled to the piston shaft 122, the second conductor707 may be coupled to the piston head 124, and the piston head 124 maybe coupled to the piston shaft 122 (e.g., using threading of the pistonshaft 122 and the piston head, using a metal joining technique, or usinga fastener).

The method 800 may further include, at 804, inserting the conductor andat least a portion of the piston into an actuator housing. For example,during assembly of the actuator 100 of FIG. 1, the piston head 124, thegland 114, the conductor 106, the guide 108, the spring element 112, theretainer 110, and at least a portion of the piston shaft 122 may beinserted into the actuator housing 102. As another example, duringassembly of the actuator 500 of FIG. 5, the piston head 124, the gland114, the conductor 106, the guide 108, the spring element 112, theretainer 510, and at least a portion of the piston shaft 122 may beinserted into the actuator housing 102. As yet another example, duringassembly of the actuator 600 of FIG. 6A, the piston head 124, the gland114, the conductor 606, the retainer 110, and at least a portion of thepiston shaft 122 may be inserted into the actuator housing 102. As stillanother example, during assembly of the actuator 700 or the actuator 750of FIGS. 7A and 7B, the piston head 124, the gland 714, at least one ofthe conductor 706 or the second conductor 707, and at least a portion ofthe piston shaft 122 may be inserted into the actuator housing 102.

The method 800 may include, at 806, coupling the piston to the actuatorhousing using a retainer assembly such that the conductor maintainselectrical contact with the piston and with the actuator housing duringreciprocation of the piston within the actuator housing. For example,during assembly of the actuator 100 of FIG. 1, the gland 114 may becoupled to the actuator housing 102, and a retaining assembly (e.g., theretainer 110, the spring element 112, and the guide 108) may be coupledto the gland 114 to retain the conductor 106 in electrical contact withthe actuator housing 102 and with the piston 120. As another example,during assembly of the actuator 500 of FIG. 5, the gland 114 may becoupled to the actuator housing 102, and a retaining assembly (e.g., theretainer 510, the spring element 112, and the guide 108) may be coupledto the gland 114 to retain the conductor 106 in electrical contact withthe actuator housing 102 and with the piston 120. As yet anotherexample, during assembly of the actuator 600 of FIG. 6A, the gland 114may be coupled to the actuator housing 102, and a retaining assembly(e.g., the retainer 110) may be coupled to the gland 114 to retain theconductor 606 in electrical contact with the actuator housing 102 andwith the piston 120. As still another example, during assembly of theactuator 700 or the actuator 750 of FIGS. 7A and 7B, the piston shaft122 or interior walls of the cylinder 104 may act as a retainingassembly to retain the conductor 706, the second conductor 707, or both,in a desired orientation such that the conductor 706, the secondconductor 707, or both remain in electrical contact with the actuatorhousing 102 and with the piston 120.

FIG. 9, a block diagram of an illustrative embodiment of an aircraft 902that includes an actuator 930 that includes internal features thatprovide a conductive path between a piston shaft of the actuator and anactuator housing of the actuator. As shown in FIG. 9, the aircraft 902may include an airframe 918, an interior 920, and a plurality of systems922. The systems 922 may include, as illustrative examples, a propulsionsystem 924 including one or more engine 926, a hydraulic system 928including the actuator 930, an electrical system 940, an environmentalsystem 950, and a communication system 960.

In a particular implementation, the airframe 918 may include or beformed at least partially of a composite material. In thisimplementation, the airframe 918 or portions of the airframe 918 may benon-conductive. When the actuator 930 is coupled to a non-conductiveportion of the airframe 918, such as a flight control surface, theairframe 918 may not provide a conductive path between the piston andthe actuator housing of the actuator 930. However, the internal featuresof the actuator 930 may provide a conductive path between the piston andthe actuator housing of the actuator 930. For example, the actuator 930may correspond to or include one or more of the actuator 100 of FIG. 1,the actuator 500 of FIG. 5, the actuator 600 of FIGS. 6A and 6B, theactuator 700 of FIG. 7A, or the actuator 750 of FIG. 7B. In each ofthese examples, the conductive path may prevent uneven buildup of chargebetween the piston and the actuator housing. Additionally, theconductive path may provide a path to ground to enable dissipation ofcurrent due to events, such as a lightning strike. Although FIG. 9specifically illustrates an aerospace application of the actuator 930,in other implementations, the actuator 930 may be used in anotherapplication, such as, as a component of a land-based vehicle (e.g., anautomobile or train), as a component of a water-based vehicle (e.g., aship or submarine), as a component of a space craft, as a component of astructure (e.g., a building, an oil platform, etc.), or as a componentof a construction equipment or lifting equipment device (e.g., a crane,a lift truck, etc.).

The illustrations of the examples described herein are intended toprovide a general understanding of the structure of the variousimplementations. The illustrations are not intended to serve as acomplete description of all of the elements and features of apparatusand systems that utilize the structures or methods described herein.Many other implementations may be apparent to those of skill in the artupon reviewing the disclosure. Other implementations may be utilized andderived from the disclosure, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof the disclosure. For example, method steps may be performed in adifferent order than shown in the figures or one or more method stepsmay be omitted. Accordingly, the disclosure and the figures are to beregarded as illustrative rather than restrictive.

Moreover, although specific examples have been illustrated and describedherein, it should be appreciated that any subsequent arrangementdesigned to achieve the same or similar results may be substituted forthe specific implementations shown. This disclosure is intended to coverany and all subsequent adaptations or variations of variousimplementations. Combinations of the above implementations, and otherimplementations not specifically described herein, will be apparent tothose of skill in the art upon reviewing the description.

The Abstract of the Disclosure is submitted with the understanding thatit will not be used to interpret or limit the scope or meaning of theclaims. In addition, in the foregoing Detailed Description, variousfeatures may be grouped together or described in a single implementationfor the purpose of streamlining the disclosure. As the following claimsreflect, the claimed subject matter may be directed to less than all ofthe features of any of the disclosed examples.

Examples described above illustrate but do not limit the disclosure. Itshould also be understood that numerous modifications and variations arepossible in accordance with the principles of the present disclosure.Accordingly, the scope of the disclosure is defined by the followingclaims and their equivalents.

What is claimed is:
 1. An actuator comprising: a piston including apiston shaft; a housing, wherein the piston is configured to reciprocatewithin the housing; and a conductor coupled to the piston within thehousing to electrically couple the piston to the housing as the pistonreciprocates within the housing.
 2. The actuator of claim 1, furthercomprising a gland coupled to the housing and surrounding the pistonshaft.
 3. The actuator of claim 2, further comprising a retainer coupledto the gland and surrounding the piston shaft to retain the conductor incontact with the housing.
 4. The actuator of claim 3, wherein the glandincludes a recess to receive at least a portion of the conductor.
 5. Theactuator of claim 4, wherein the recess is mechanically coupled to aretainer assembly, wherein the retainer assembly retains the conductorin electrical contact with the gland.
 6. The actuator of claim 3,wherein the conductor comprises a plurality of spring fingers arrangedin a ring around the piston shaft.
 7. The actuator of claim 3, whereinthe conductor comprises a split ring arranged around the piston shaft.8. The actuator of claim 7, wherein the split ring includes a curvedbody defining a first end and a second end, the first end and second endseparated by a gap of the split ring, wherein a thickness of the curvedbody tapers toward the first and second ends.
 9. The actuator of claim7, wherein the split ring includes a curved body defining a first endand a second end, the first end and second end separated by a gap of thesplit ring, wherein a thickness of the curved body is uniform betweenthe first and second ends.
 10. The actuator of claim 8, wherein thesplit ring further includes a first elongated member coupled to thefirst end and extending radially from the curved body and a secondelongated member coupled to the second end and extending radially fromthe curved body.
 11. The actuator of claim 1, wherein the housingdefines a chamber to retain a working fluid, wherein the conductorcontacts the housing and the piston shaft external to the chamber, andwherein the conductor maintains sliding contact with the piston shaft asthe piston reciprocates within the housing.
 12. The actuator of claim 1,wherein the housing defines a chamber to retain a working fluid, andwherein the conductor contacts the housing and the piston shaft internalto the chamber.
 13. The actuator of claim 12, wherein a first end of theconductor is coupled to a first side of a piston head of the piston anda second end of the conductor is coupled at to an interior wall of thehousing.
 14. The actuator of claim 13, further comprising a secondconductor within the chamber, wherein a first end of the secondconductor is coupled to a second side of the piston head and a secondend of the second conductor is coupled to a second interior wall of thehousing.
 15. A vehicle comprising: an actuator comprising: a pistonincluding a piston shaft; a housing, wherein the piston is configured toreciprocate within the housing; and a conductor coupled to the pistonwithin the housing to electrically couple the piston to the housing asthe piston reciprocates within the housing.
 16. The vehicle of claim 15,further comprising one or more wings and a fuselage, wherein at leastone of the one or more wings or the fuselage includes a compositestructural member, a metallic structural member, or a combinationthereof, coupled to the actuator.
 17. A method comprising: coupling aconductor to a piston such that the conductor is in electrical contactwith the piston; inserting the conductor and at least a portion of thepiston into an actuator housing; and coupling the piston to the actuatorhousing using a retainer assembly such that the conductor maintainselectrical contact with the piston and with the actuator housing duringreciprocation of the piston within the actuator housing.
 18. The methodof claim 17, wherein coupling the conductor to the piston comprisesattaching a first end of the conductor to a piston head of the piston,and further comprising attaching a second end of the conductor to aninterior wall of the actuator housing.
 19. The method of claim 17,further comprising: coupling a gland to the actuator housing andsurrounding a piston shaft of the piston; and coupling a retainer to thegland and surrounding the piston shaft to retain the conductor incontact with the actuator housing.
 20. The method of claim 17, whereinthe conductor comprises a split ring arranged around a piston shaft ofthe piston, wherein the split ring includes a curved body defining afirst end and a second end, the first end and second end separated by agap of the split ring, wherein a thickness of the curved body taperstoward the first and second ends.